1. Field of the Invention
Substantially large amounts of silver are employed in the development of photographs. With the increasing shortage of silver and its concomitant increase in price, efficient, inexpensive procedures for recovering the silver are desirable. In order for a procedure to be satisfactory, it must have a high efficiency in removing substantially all of the silver ion from the solution, reducing it to the silver metal. The silver metal must be produced in a form substantially free of contaminants and readily isolatable. Furthermore, it is desirable to be able to re-use the resulting solution, rather than discarding the relatively expensive chemicals which are employed in the photographic development process. Therefore, in reducing the silver, it is preferable that the oxidized form of the reducing agents employed in the developing solution should also be reduced. Not only should they be reduced, but they should be returned to the solution in a form useful for re-use of the development solution.
Description of the Prior Art
Metals have been employed, such as iron, zinc and copper for recovery of silver. However, these metals do not provide a rejuvenated development solution, and the resulting metal salts can be harmful contaminants and pollutants. Eastman Kodak commercially supplies a silver-recovery system providing renewable cartridges employing iron mesh.